goedon



UNTTED STATES PATENT OFFICE.,

JAMES E. H. GORDON, OF HOLMWOOD COTTAGE, DORKING, ENGLAND.

ELECTRIC LIGHT.

SPECIFICATION forming part of Letters Patent No. 234,770, dated November 23. 1880.

Application tiled October 2, 1880.

To all whom it may concern Beit known that l, J AMES EDWARD HENRY GORDON, a subject ot" the Queen of Great Britain, residing at Holmwood Cottage, Dorking, in the county ot' Surrey, England, have invented certain new and useful Improvements in Electric Lighting, for which I have received Letters Patent in England, No. 1,826, dated May 4, 1880; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same.

I make use ot' the discoveryannounced last year by Mr. Spottiswoode in the London, Edinburgh, and Dublin Philosophical Magazine, that an induction-coil can be excited by aDe Meritens or other magneto-electric or dynamo-electric machine giving alternate currents, and that no contact-breaker or primary condenser are required.

I place a number of induction-coils on one machine, either in series or in parallel circuit, or in anycombination ot' the two. The machine excites the coils, and the light is obtained from the secondary currents.

The magneto-electric or dynamo-electric machine must be one that gives rapid and sharp reversals.

The lamps consist of lumps or knobs of refractory metal xed on thin stems of the same. The secondary discharge passes from onelump to another and heats the lumps, which glow and give the light. The thin stems prevent the heat being conducted away too rapidly.

The following form of the lamp has been found to be the most advantageous, but is not the only useful form Four pear-shaped knobs, each carried by a wire stem, are placed in a line near together, and the two outside ones connected to the secondary coil. When the discharge passes the two outer knobs get moderately hot and the two inner ones very hot. The two outer knobs may be platinum and the two inner ones iridium or iridio-platinum alloy. The sizeof the knobs varies according to the strength of the current from about that ot' a pins head to that of avsmall pea. It is sometimes advantageous to make all four knobs of iridium, and to make the two outer ones much. smaller than the inner ones. The stems (No model.) Patented in England May 4, 1830.

are preferably ot' platinum -or platinum-iridium alloy, and I use wires about two to three. inches long and about .Oli inch thick, the object being to have them the thinnest which which will be sat'e from melting. The distance apart ot' the knobs when cold should be such that they just do not touch when ex# paudcd by heat. A separate induction-coil mayr be used for each lamp, or several lamps can be placed on onecoil,as follows first, they may be all placed in series; second, a better plan is to let each lamp have its own section ot' the secondary wire. This latter plan makes all the lamps in a coil nearly independent ot' each other. The lamps may be lighted and extinguished either by a make-and-break key in the secondary circuit, or by short-circuiting the secondary or the lamps may be lighted and extinguished by shunting the primary current on and off the coil, or on and oit' several coils at once, with or without the introduction ot` a compensating resistance.

To give some idea ot' the dimensions ot' the coils I give the details of one which I have used for one one-hundred-candle light or two titty-candle lights. The primary consists` ot' a bundle ot iron wires 1.3 inch ldiameter and eighteen inches long. Three layers of insulated wire .08 inch in diameter are wound on it. The secondary is wound on an insulating-tube, and consists of about two-thirds ot' a mile ot' wire .0075 inch diameter covered four times with silk. It is wound in sixty disks. The external diameter ot the secondary coil is about 3.5 inches. There are three binding-screws, one at each end and one in the center, so that the whole coil can be used for one lamp or either half separately.

I have given the above details as examples of what may advantageously be used with an ordinary Rhumkorff coil; butI do not restrict myself to the use of this class of coil, as many other forms of induction-coils might be used.

I would also state that although I believe it to be best to work the lamp with alternate currents of high tension obtained in the way above described, yet that it may be used with alternate currents of sufficiently-high tension obtained in other ways.

I consider that the new light has the follow- IOO ing special advantages: The accidental destruction of any lamp extinguishes that lamp only, the light is capable of great subdivision there is no carbon or anything else consumed in the lamps; there is no vacuum and no clockwork; the light is extremely steady.

The drawing shows a section of an electric lamp constructed according to my invention.

A is a glass globe, held, as shown, by screws A to the under side of a plate, B, ot' glass or porcelain. G is a plate of ebonite carried by brass pillars D from the plate B. D are nuts screwing onto the pillars D and holding the plates. Dzis a cross-head on the lower end of each pillar. The screws A screw through these heads.

E is an opaque shade by which the plates B and C may bc surrounded. E' are arms fixed to the plate B. By these arms the lamp can be suspended by chains F, as shown.

G are four stems ofnlatinum wire with knobs H of iridiuni on their lower ends. The upper ends of the wire stems are fixed to the caps or solid tops of tubes I, which are carried by the ebonite plate C. The two outermost wire stems are coupled by wires J to the source of the apidly-alternatin g currents of electricity. The Suspenders can, if desired, be used as conductors.

Through the sides of each of the tubes lare screwed three adjusting-screws. The ends ot' the screws bear against the wire stems, and by means of them the knobs at thelower ends of the stems can be held and retained at any required distance apart from one another.

There are holes K in the plates B and O through which the wire stems G pass. These holes also serve to admit currents of cool air to the interior of the globe A.

L is a chimney, by which heated air can rise up and escape from the globe.

I would remark that l do not confine myself to the use of myla-mp in conjunction with induction-coils, for I have found that it may be worked direct by a machine which yields alternate currents of high intensity, and such machines are now produced by De Meritens. lt is found that much greater tension is required to light the lamps-' z. c., to cause the spark to spring between the cold knobs-than to maintain them when lighted. Now, al-

though it is perfectly possible to produce a current ot' sufciently-high tension, either by a machine or by an induction-coil, to light the lamps, yet it is found that as every increase of tension throws an extra strain on the insulation it is advantageous to bring the four knobs into contact, or nearly into contact, before the lamp is lighted and to separate them after the current has begun to pass. This may either be done by hand, by the use of suitable levers, or automatically by a lever or levers acted on by the passage of the electric current, or by the heat generated by it, or otherwise.

I do not broadly claim herein the use of an induction-coil to produce an electric light, being aware that such a device is old.

What I claim isl. The combination, substantially as herein set forth, of a series of thin stems or conducting-wires, each terminating in an incandescing lump of refractory metal adjacent to but not touching its neighbor, whereby the lumps are rendered luminous by incandescence while the current passes from one lump to another.

2. The combination, substantially as herein set forth, of a magneto-electric or dynamo-electric machine yielding an alternating electric current of high intensity and with rapid and sharp reversals, and a series of thin stems or conducting-wires each terminating in an incandescing lump of refractory metal adjacent to but not touching its neighbors.

3. The combination, substantially as herein set forth, of a magneto-electric or dynamo-electric machine and an induction coil or coils, the terminals of which constitute thin stems carrying lumps of refractory metal adjacent to but not touching each other, which lumps are heatedby the discharge in the secondary circuit or circuits of the induction-coil.

4. The combination, substantially as herein set forth, ot' the support C, the thin stems or conducting-wires passing therethrough, the lumps of refractory metal mounted on the stems, and the adjusting-screws for regulating the distance between the lumps.

J. E. H. GORDON.

Witnesses:

CHAs. BERKLEY HARRIS, J. WATT,

17 Gracechurch Street, London. 

